As I see,
chrox in Github issues is trying various methods for invoking KPV for supported file types. I think, it will be worth to him to know that system Reader booklet supports plugins. Enabled plugins are listed in
reader_plugins.xml. In Kindle Touch this file is located in
/opt/amazon/ebook/config/, but it looks like in PW it's embedded into
/opt/amazon/ebook/lib/ReaderSDK-impl.jar (but still in a form of easily accessible text file).
I believe, that filetype-dependent part of system reader code is located in plugins that are defined in
reader_plugins.xml.
yifanlu tried to reverse engineer plugin interface for 5.0.0 and implement it's own, invoked for EPUB files:
https://github.com/yifanlu/KindleEPU...lu/kindle/epub. It could help, but code is in unfinished state.
(I can't post to Github right now, sorry.)